Cyclic-di-GMP induces STING-dependent ILC2 to ILC1 shift during innate type 2 lung inflammation
Type 2 inflammation is found in most forms of asthma, which may co-exist with recurrent viral infections, bacterial colonization, and host cell death. These processes drive the accumulation of intracellular cyclic-di-nucleotides such as cyclic-di-GMP (CDG). Group 2 innate lymphoid cells (ILC2s) are critical drivers of type 2 lung inflammation during fungal allergen exposure in mice; however, it is unclear how CDG regulates lung ILC responses during lung inflammation. Here, we show that CDG induced early airway type 1 interferon (IFN) production and dramatically suppressed both lung proliferating CD127+ST2+ ILC2s and Alternaria- and IL-33-induced lung inflammation. Further, transcriptomic analysis of CD127-ST2- Thy1.2+ ILCs, which were expanded and activated by CDG, revealed an ILC1 signature. CDG administration led to accumulation of IFN{gamma}+ and T-bet+ ILC1s, as well as neutrophilia, independent of IL-18R, IL-12, and STAT6 but dependent on stimulator of interferon genes (STING) and partially dependent on type 1 IFN signaling. Thus, CDG potently suppresses ILC2-driven lung inflammation and promotes ILC1 responses. These results suggest potential therapeutic modulation of STING to suppress type 2 inflammation and/or increase anti-viral responses during respiratory infections.